Spatial contrast sensitivity was used to assess losses or changes in overall visual resolution in patients having a variety of toxic, inflammatory, degenerative, or congenital retinal and neuro-ophthalmological disorders of the visual system. A criterion-free forced-choice psychophysical procedure was used, since this method was previously shown to minimize spurious changes in sensitivity was repeated testing. During this past year, the use of technique was broadened to include the evaluation of vision in cataractous patients and to evaluate a hypothesis concerning the relationship between blood sugar level and contrast sensitivity in diabetic patients.